Various publications, including patents, published applications, technical articles and scholarly articles are cited throughout the specification. Each of these cited publications is incorporated by reference herein, in its entirety and for all purposes.
Several surgical techniques have been developed to address spinal defects, such as disc degeneration and deformity. Spinal fusion has become a recognized surgical procedure for mitigating back pain by restoring biomechanical and anatomical integrity to the spine. Spinal fusion techniques involve the removal, or partial removal, of at least one intervertebral disc and preparation of the disc space for receiving an implant by shaping the exposed vertebral endplates. An implant is then inserted between the opposing endplates.
The surgical procedure corresponding to an implant system should preserve as much vertebral endplate bone surface as possible by minimizing the amount of bone removed. This vertebral endplate bone surface, or subchondral bone, is generally much stronger than the underlying cancellous bone. Preservation of the endplate bone stock ensures biomechanical integrity of the endplates and minimizes the risk of implant subsidence. Thus, proper interbody implant design should provide for optimal seating of the implant while utilizing the maximum amount of available supporting vertebral bone stock.
Nevertheless, traditional implantation practices often do not preserve critical bone structures such as vertebral endplates during the surgical procedure. In some cases, the implant devices themselves necessitate removal of bone and were not designed or implanted with the intent to preserve critical bone structures during or after implantation.
In addition, traditional implantation procedures require an incision large enough to fit the full implant through, and require sufficient dissection of internal tissues in order to provide a clear pathway from the incision to the implantation locus. The incision and dissection necessarily cause tissue trauma, tend to increase pain and discomfort, and prolong recovery time in the patient, and also may increase the chances of a complication to the patient resulting from the implantation procedure. Accordingly, there is a standing need to reduce tissue trauma in implantation patients. It is a general desire to reduce the size of the implant such that the incision and tissue dissection can be minimized, yet any reduction in size must be balanced with the need for the implant to adequately stand in the place of the tissue it replaces. In other words, an implant that is smaller must still be able to adequately bear the load in the body.